taos> select CHAR(77)
 char(77) |
===========
 M        |

taos> select CHAR(77.5)
 char(77.5) |
=============
 M          |

taos> select CHAR(100)
 char(100) |
============
 d         |

taos> select CHAR(77) from ts_4893.meters limit 5
 char(77) |
===========
 M        |
 M        |
 M        |
 M        |
 M        |

taos> select CHAR(77,78,79,80,81) from ts_4893.meters limit 5
  char(77,78,79,80,81)  |
=========================
 MNOPQ                  |
 MNOPQ                  |
 MNOPQ                  |
 MNOPQ                  |
 MNOPQ                  |

taos> select CHAR(77*256+77) from ts_4893.meters limit 5
 char(77*256+77) |
==================
 MM              |
 MM              |
 MM              |
 MM              |
 MM              |

taos> select concat(CHAR(77),CHAR(78)) from ts_4893.meters limit 5
 concat(char(77),char(78)) |
============================
 MN                        |
 MN                        |
 MN                        |
 MN                        |
 MN                        |

taos> select cast(CHAR(49) as int)
 cast(char(49) as int) |
========================
                     1 |

taos> select CHAR(id + 77) from ts_4893.meters order by ts limit 5;
 char(id + 77) |
================
 M             |
 N             |
 O             |
 P             |
 Q             |

taos> select CONCAT(CHAR(id + 77),CHAR(id + 77),CHAR(id + 77)) from ts_4893.meters limit 5
 concat(char(id + 77),char(id + 77),char(id + 77)) |
====================================================
 MMM                                               |
 NNN                                               |
 OOO                                               |
 PPP                                               |
 QQQ                                               |

taos> select CHAR(id+77, id+77, id+77, id+77, id+77) from ts_4893.meters limit 5
 char(id+77, id+77, id+77, id+77, id+77) |
==========================================
 MMMMM                                   |
 NNNNN                                   |
 OOOOO                                   |
 PPPPP                                   |
 QQQQQ                                   |

taos> select char(77)
 char(77) |
===========
 M        |

taos> select char(77 * 256 + 77)
 char(77 * 256 + 77) |
======================
 MM                  |

taos> select char('123')
 char('123') |
==============
 {           |

taos> select char(77, NULL, '123')
 char(77, null, '123') |
========================
 M{                    |

taos> select char(null)
 char(null) |
=============
            |

taos> select char('ustc')
 char('ustc') |
===============
              |

taos> select char(65.99)
 char(65.99) |
==============
 A           |

taos> select char(65, 66, 67)
 char(65, 66, 67) |
===================
 ABC              |

taos> select char(72, 101, 108, 108, 111)
 char(72, 101, 108, 108, 111) |
===============================
 Hello                        |